This invention relates to processes for separating metals. More particularly, it is concerned with a process for separating tungsten from coinage metals, notably silver, during electrowinning.
In the manufacture of electrical switchgear equipment, relays, motor controllers and the like, composites or alloys of tungsten and coinage metals, especially silver, are used as electrical contact points. Cost considerations dictate that both tungsten and silver be recovered from any scrap generated by the manufacturing process.
It has been the practice in the art to recover silver or other coinage metal from tungsten-containing alloys by conventional electrowinning processes. A major drawback of such methods, however, is the codeposition of tungsten with the coinage metal at the cathode of the electrowinning cell resulting in unwanted contamination of the recovered coinage metal by tungsten.